Ladder rung fastening means



.Feb. 4, 1947. E. 1'. JOHN LADDER HUNG FASTENING MEANS Filed May 27, 1944 Eowmzu T. J0me v A w\ Patented Feb. 4, 1947 UNITED STATES. PATENT OFFICE LADDER HUNG FASTENING MEANS Edward T. John, Minneapolis, Minn, assignorto- The J K. Clark Company, Minneapolis, Minn., a corporation. of Minnesota Application May 27,1944,.Seriall*lo. 537,747-

1- Claim. 1

This invention relates to improvements in means for fastening ladder rungs in the stiles.

The primary object of my invention is to provide means for this purpose by which the rungs of a ladder may be securely fastened in the stiles as well as anchored against turning, in amanner such as to reduce the time and labor necessary in manufacturing the ladder.

It is the almost universal present practice, to my knowledge, to fasten the rungs. in the ladder stiles by means of nails which are driven through one edge of the stiles and into round tenons on the rung ends, which aredisposed in appropriately bored holes in the stiles. The nails thus serve not only to keep the stiles from spreading but tolock the rungs from turning in the round holes in the stiles. However; the nailing operation requires considerable time and labor and in addition, the nailing is found to weaken the stile or cause it to split about the nails as time goes on.

Furthermore the production of ladders by this method is hindered by the fact that the ladder must remain in the bench, or the machine in which the stiles and rungs are assembled and the stiles pressed toward each other onto the ends of the rungs, while the entire nailing operation on all rungs is carried out. The bench, it may be noted, has opposed jaws and members which in operation engage outer sides of the stiles and press them inward, causing. the ends of the rungsto enter the'holes-in the stiles, and holding the entire structure in assembled relation while the rungs are fastened.

In accordance with my invention, and as an object thereof, I provide fastening means which eliminates the nailing operation entirely while providing a fastening of equal or greater strength, and which permits the rungs to be fastened in response only to the pressing or clamping action of the bench jaws as they force the stiles into the rung ends. Thus it will be evident that the ladder is completely assembled immediately'asthe stiles are forced home and the ladder need. not

remain in-the bench while being nailed, thu effecting a substantialsaving in. the time required for assembly.

These and other more detailed and specificob jects will be disclosed inthecourse of the following specification, reference being had to the accompanying drawing, in which Fig. 1 is a fragmentary sectional view of a lad der rung and associated stiles, indicating the manner in which the latter are pressed home on the rungs, and showing my improved fastening means in use.

2 Fig. 2 is a perspective view of adjacent portions of a ladderrung and stile; prepared in accordance with my invention.

Fig. 3'is a perspective view of oneformoffas tening means for use in connection with thestile and rung'as shown in Fig. 2. g

Figs. 4 and 5 are similar enlarged sectional details illustrating successive steps in the fastening of the rung in the stile.-

Fig. 6 is a fragmentary outside elevationof a ladder stile having a rungfastened therein in accordance with my invention.

Referring now more particularly and by reference characters to the drawing, A designates a rung of a ladder and B the stiles between which the mug isplaced and secured. 'I'he-rungswhen properly fastened areheld against turning and cooper-ate to hold the stiles B in properlyas-- sembled spaced relation. Ordinarily the rungs; which are themselves ordinarily circular in'cross section; are provided for this purpose with reduced round tenons atieach end which enter complementarily shaped openings bored; in the stiles, and' as pointed out, the tenons are anchoredin these openings by drivin nails through an edgeof each stile into the tenon along a line radial" thereto. Whilebeing'thus nailed the ladder is held in a horizontal position in anassembling machine,. called: a bench, and which includes a series of: jaws or clamps C a pair of which is shown at (Fig. 1), operative tOeng-age outer sides or the stiles B to force them over the rungsandclamp them in place with the ladder properly shaped and assembled.

In accordance with my invention I provide each rung A with a tenon H)" at each end which is of a cross sectional shape other than round and which is fitted into a correspondingly shaped opening II in the stile so that the rung" cannot turn, and the necessity for-nailing on this account is eliminated. against endwi'se displacement with respect to the stiles, or conversely to hold" the latter against spreading, I provide fastening means in the-form of a ferrule or ferrule-like member which is fitted over the tenon land-which is upset or expanded during the assembly operation in such manner as to securely lock the rung andst-iles' together.

As seen in Fig. 2 each tenon I!) is preferably square in cross section and this shape is advantageous not alone for locking the rung against rotation but for strength also since a tenon of a cross sectional area at least as great as that of the usual round one may thus be obtained. The open- To then hold the runs ings I I in the stiles are of the same shape but are slightly larger, and are provided around outer ends or edges with enlargements such as the bevels or shoulders indicated at I2. In accordance further with my invention the tenon I is provided intermediate the ends with an encompassing groove indicated at I 3, extending entirely around its four sides.

To fit the tenon In I provide the ferrule member indicated generally at I4 which is formed from a sheet metal blank of suitable gauge and material and is initially fiat and cruciform in shape as seen in Fig. 3. The ferrule has four sides or arms I5 which are joined by and extend from a center portion I6 and these sides are bent in the same direction along lines I'I so that they will fit over and substantially cover the four sides of tenon ID. The length of the sides I5 is, however, such that the center portion 6, now forming the closed end of the substantially tubular ferrulelike member thus formed, initially stands in spaced relation to the end of the tenon Ill as indicated at I8 in Fig. 4, while the other or open end of the ferrule butts against the shoulder I9 at the junction of the tenon and rung A. The sides I5 are formed with transversely extending pressed ribs or beads 2Il'so located and shaped as to extend and fit inwardly into the groove I3 on all four sides of the tenon I0, and while so positioned, to lock the ferrule against endwise displacement from the tenon.

Preliminary to the assembly of the ladder each rung is provided at each end with a ferrule member folded over its sides to bring the locking ribs 20 into the grooves I3. The ladder is then assembled in the bench in the usual manner with the stiles B at greater than usual spacing and the rungs A disposed at intervals therebetween, ready to enter the openings II in the stiles. As the bench jaws 0 now are moved together the stiles are pressed onto the rungs, the ferrules I4 entering and nicely fitting the openings H so that the sides I5 cannot spread and release the locking engagement between the ribs 20 and grooves I3. As the stiles are forced home the closed ends of the ferrules completely penetrate the openings I l and the ferrule, being initially larger than the thickness of the stiles (Fig. 4) it will be apparent that said closed ends I6 will come to bear on inner faces of. the bench jaws C before the ferrules are entirely home in the stiles. Thus as the stiles are pressed fully onto the rungs the pressure exerted upon the closed ends of the ferrules can only result in the spreading or upsetting of these ends, causing them to swell into the space provided by the aforesaid enlarged outer ends I2 of the openings II as indicated at 2| in Figs. '1 and 5. What occurs is, that the sides I5 buckle or expand outwardly at their junctions with the center or closed ends I6 of the ferrules as will be clearlyapparent in Figs. 5 and 6, the outer ends of the ferrules are thus enlarged so that they cannot pull through the openings II.

. The outer ends of the ferrules remain substantially flat and flush with outer sides of the stiles as shown and are pressed home into the wood so that the stiles cannot move with respect to the rungs It will be clearly evident that this entire fastening operation is completed instantly as the stiles B are pressed fully home on the ends of the rungs, and that the ladder may then be immediately removed from the bench to make way for the next, without requiring that the bench operation be held up while a number of nails are driven. The application of the ferrules to the rungs, prior to assembly, may be carried out very rapidly by proper machinery and once formed onto the tenons the ferrules will remain in place until assembly due to engagement of the ribs with the grooves I3.

Obviously I might employ a tubular ferrule, that is, one in which the sides form a complete enclosure for the tenon or might use a two-sided U-shaped member (eliminating an opposed pair of the sides I5) and such variations are considered to lie within the scope of my invention. The cross sectional shape of the tenons might also be other than square as here shown, for example triangular, octangular, or even oval and any such shape would obviously serve to prevent rotation of the rungs and when fitted with a properly shaped ferrule could be locked in the stiles in exactly the same manner as hereinabove described.

It is understood that suitable modifications.

may be made in the structure as disclosed, provided such modifications come Within the spirit and scope of the appended claim.

Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

The combination with a ladderstile having an opening marginally enlarged at. its outer side and a ladder rung having a tenon adapted to penetrate said opening out to the enlarged outer end thereof, of a ferrule member having a center portion and arms turned therefrom to operatively.

embrace the tenon, and the junctions between the center portion and arms of the ferrule member being buckled outwardly into the enlarged outer end of the opening to lock the tenon therein.

EDWARD T. JOHN.

REFERENCES crrsn The following references are of record in the file of this patent:

UNITED STATES PATENTS British Mar. 30, 1898 

